QUINONES 227 







HO^J-v^(CH2)i3CH=CH(CH2)3CH3 



H3C J OH 

 



maesaquinone 



Maesa javonica, Myrsinaceae 



O 9^3 p,TT 



H0\^-V/CHCH2CHoCH=C 



HaC^ 

 O 



perezone 



Perezia adnata, Trixis calcalioides, tribe Mutisieae of the Compositae 



The Myrsinaceae seem to be particularly rich in benzo- 

 quinones, and these compounds should prove to be useful as system- 

 atic criteria. It is significant that the plants which produce benzo- 

 quinones bear no particular taxonomic affinities to those species pro- 

 ducing the other classes of quinones. 



Since these compounds are, for the most part, relatively 

 simple derivatives of naphthoquinone, it is probable that they have 

 arisen independently in many, if not all, of the families known to 

 produce them. 



Extensive surveys for the presence of naphthoquinones have 

 not been made, and many naphthoquinone-containing species may re- 

 main undetected. Naphthoquinones, by present knowledge, are rather 

 rare, and a given type usually is restricted to one or two famihes. The 

 simple naphthoquinone, juglone, approaches a familial character in 

 the Juglandaceae. Although naphthoquinones seem to be of fittle 

 systematic significance above the family level, it is possible that at 

 the lower taxonomic levels the compounds may be of systematic value. 



The most complex group of quinones, the anthraquinones, is 

 also the most widely distributed. In fact, if the three sub-types of 

 quinones were selected to illustrate the principle of the "percentage 

 of frequence" rule (see Fig. 4-1) the results would contradict the 

 principle, since the least complex have the most fimited taxonomic dis- 

 tribution. Coupled with the fact that there is little simultaneous occur- 

 rence of two or three sub-types of quinones, their general pattern of 

 distribution implies that there is no close biosynthetic relationship 

 between the types of quinones, and therefore this chemical class, in a 

 biosynthetic sense, appears to be artificial. (In contrast, in the fungal 



